We too have a rope and winch system, the rope goes from the winch warping drum and through a snatch block approx 10 mtrs from top of the ramp,and directly to the trailer. We do it this way as our ramp is older and rated to 500kgs any one load. You can launch 2 boats at a time by doing without the winch and use the boat going down the ramp to haul out the empty trailer coming up, takes a bit of clever and attentive hands on, but we can launch 15 – 20 boats within half an hour. the winch is over engineered so that it will last us a while, from memory it is rated to around 2000kg as is the snatch block and shackles
Wayne Henderson
The Flying Fifteen Blog 